1. Field of the Invention
The present invention relates to a technique of a microscopic imaging apparatus that can make time lapse capturing of a sample to be observed at arbitrary capturing intervals.
2. Description of the Related Art
Conventionally, there is a method called time lapse capturing for observing a sequential change in a sample such as a live cell, etc. in a microscopic imaging apparatus. To observe a sequential change in a sample with time lapse capturing, an image of the sample must be repeatedly obtained at arbitrary capturing intervals instructed by an operator.
For example, a digital imaging apparatus that obtains an image by exposing an imaging device such as a CCD (Charge Coupled Device), etc. to light can obtain an image at a capturing interval depending on the number of pixels read from the imaging device. Additionally, an arbitrary capturing interval can be set by repeating still image shooting with a timing signal that is generated by external software or hardware if the capturing interval is sufficiently long with respect to the length of time required to shoot a still image.
Patent Document 1 proposes the technique for shooting an image at short capturing intervals only in an important section. With this technique, a capturing interval is set to a short interval by detecting an external trigger, and captured frames are stored in an internal memory. Moreover, an external frame output is delayed to output frames at normal capturing intervals, and a sequential change in an observation target in an important section is finely checked.
Additionally, Patent Document 2 proposes the technique for implementing an arbitrary capturing interval. With this technique, an arbitrary capturing interval is implemented by changing the frequency of a clock supplied to an imaging device and its peripheral imaging device driving circuit.
[Patent Document 1] Japanese Patent Publication No. 2003-087630
[Patent Document 2] Japanese Patent Publication No. 2005-175774